-module(app_manager).

-behaviour(gen_server).

%% API
-export([start_link/0]).
-export([regist/1]).
-export([unregist/1]).
-export([lookup/1]).
-export([regist_from_file/1]).
-export([query_app/0]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
         terminate/2, code_change/3]).

-record(state, {}).




-include("xengine.hrl").
-include_lib("stdlib/include/qlc.hrl").


lookup(AppName)->
        configuration_manager:lookup(app,AppName).


query_app()->
         gen_server:call(?MODULE, {query_app} ).

        
regist_from_file(File) ->
        case   file:consult(File) of
                {ok , Apps } ->
                    gen_server:call(?MODULE, {regist, Apps} ) 
        end.        

regist(App)   ->
        gen_server:call(?MODULE, {regist, App} ).

unregist(AppName)->
                gen_server:call(?MODULE, {delete, AppName} ).


%%====================================================================
%% API
%%====================================================================
%%--------------------------------------------------------------------
%% Function: start_link() -> {ok,Pid} | ignore | {error,Error}
%% Description: Starts the server
%%--------------------------------------------------------------------
start_link() ->
    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).

%%====================================================================
%% gen_server callbacks
%%====================================================================

%%--------------------------------------------------------------------
%% Function: init(Args) -> {ok, State} |
%%                         {ok, State, Timeout} |
%%                         ignore               |
%%                         {stop, Reason}
%% Description: Initiates the server
%%--------------------------------------------------------------------
init([]) ->
    {ok, #state{}}.

%%--------------------------------------------------------------------
%% Function: %% handle_call(Request, From, State) -> {reply, Reply, State} |
%%                                      {reply, Reply, State, Timeout} |
%%                                      {noreply, State} |
%%                                      {noreply, State, Timeout} |
%%                                      {stop, Reason, Reply, State} |
%%                                      {stop, Reason, State}
%% Description: Handling call messages
%%--------------------------------------------------------------------
handle_call({query_app},_From,State)->
        {reply ,  
         lists:map(fun (App) ->
                      { App , length(instance_manager:lookup_containers_by_app(App#app.name))}
                   end,
                   configuration_manager:do(qlc:q([X || X <- mnesia:table(app)])))    ,
          State};
handle_call({unregist, AppName}, _From, State) -> 
        {reply , configuration_manager:delete(app,AppName) , State } ;
handle_call({regist, App}, _From, State) -> 
        {reply , configuration_manager:insert(App) ,State } ;
handle_call(_Request, _From, State) ->
        Reply = ok,
        {reply, Reply, State}.

%%--------------------------------------------------------------------
%% Function: handle_cast(Msg, State) -> {noreply, State} |
%%                                      {noreply, State, Timeout} |
%%                                      {stop, Reason, State}
%% Description: Handling cast messages
%%--------------------------------------------------------------------
handle_cast(_Msg, State) ->
    {noreply, State}.

%%--------------------------------------------------------------------
%% Function: handle_info(Info, State) -> {noreply, State} |
%%                                       {noreply, State, Timeout} |
%%                                       {stop, Reason, State}
%% Description: Handling all non call/cast messages
%%--------------------------------------------------------------------
handle_info(_Info, State) ->
    {noreply, State}.

%%--------------------------------------------------------------------
%% Function: terminate(Reason, State) -> void()
%% Description: This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any necessary
%% cleaning up. When it returns, the gen_server terminates with Reason.
%% The return value is ignored.
%%--------------------------------------------------------------------
terminate(_Reason, _State) ->
    ok.

%%--------------------------------------------------------------------
%% Func: code_change(OldVsn, State, Extra) -> {ok, NewState}
%% Description: Convert process state when code is changed
%%--------------------------------------------------------------------
code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------

